Brake assembly



Nov. 29, 1949 R. R. CROOKSTON BRAKE ASSEMBLY Filed Aug. 19, 1946 4 Sheets-Sheet 1 F I G. I.

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Nov. 29, 1949 R. R. CROOKSTON 2,489,449

BRAKE ASSEMBLY Filed Aug. 19, 1 946 4 Sheets-Sheet 2 i\ 20 I 23 2| I r 25 C ow "11v 25 K 6' r 27 f L If 28 L 32 (3 29 L, I) LA k; x O L. 38

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a L 39 a '1 Nov. 29, 1949 R. R. CROOKSTON BRAKE ASSEMBLY Filed Aug. 19, 1946 4 Sheets-Sheet 3 fio/mo/ INIV/ENTIOR.

Patented Nov. 29, 1949 BRAKE ASSEMBLY Robert R. Crookston, Houston, Tex., assignor, by

mesne assignments, to Standard Oil Development Company, Elizabeth, N. J., a corporation of Delaware Application August 19, 1946, Serial No. 691,486

The present invention is directed to a device adapted to control the speed of rotation of a body mounted for movement about a fixed axis. More particularly, the present invention is a device adapted to control the rate of rotation of a hoisting drum which is supporting a load by means of a line wound on the body of the drum.

For example, in the drilling of a borehole by the rotary drilling method, the drill stem employed when drilling deep holes is so long that the total weight of the drill stem is not allowed to rest on the drill bit and in such operations a part of the weight of the drill stem is taken by the travelling block which in turn is suspended from the crown block of the derrick by the hoisting line which has an end attached tothe hoisting drum or draw works. In order to have an efficient operation, it is desirable that the load carried by the drill bit be relatively uniform. If insufficient weight is carried on the bit, it does not penetrate as rapidly as is desirable while if the weight carried by the bit is excessive the hole produced may be. crooked or the drill stem may be twisted off.

It is an object of the present invention to produce an arrangement which allows the speed of rotation of a hoisting drum to be accurately controlled while producing a minimum amount of shock and irregularity of movement of the hoisting drum. I

It is a further object of the present invention to produce a device which is capable of closely controlling the speed of rotation of a hoisting .drum carrying a heavy load supported by a line and which is capable of terminating the rotating movement substantially instantaneously whenever desired by the operator.

It is a further object of the present invention to devise a means for controlling the-speed of rotation of a hoisting drum to be controlled with little manual effort by an operator.

Other objects and advantages of the present invention may be seen from the following description taken in conjunction with the drawing in which Fig. 1 is a front elevation with parts cut away showing an embodiment of the present invention;

Fig. 2 is a side elevation, with some parts cut away and some parts shown in section;

Fig. 3 is a view taken along line IIIIII of Fig. 1;

10 Claims. (Cl. 188-151) Fig. 4 is a view showing in detail the construction of a valve of the assembly of Fig; 1;

Fig. 5 is a view showing in detail the movable element of the valve shown in Fig. 4;

Fig. 6 is a view showing in detail the construction of another of the valves of the assembly of Fig. 1;

Fig. 7 is a flow diagram showing the conduits fluidly connecting the various parts of the apparatus illustrated in Fig. 1; and

Fig. 8 is a fragmentary view showing electrical means used for operating a portion of the apparatus.

The device of the present invention may be described briefly as involving a plurality of brake bands mounted on a frame supporting a hoisting drum with the brake bands arranged for limited arcuate movement and control means for tightening one band while the other is loose and for regulating the movement of the tight band and control means for simultaneously tightening all of the bands to stop completely the rotation of the hoisting drum.

In its more specific aspects, the device of the present invention involves two brake bands mounted on a frame supporting a hoisting drum and arranged for limited arcuate movement with the axis of the movement of the brake bands coinciding with the axis of rotation of the hoisting drum. Each brake band is mechanically connected to a piston slidably arranged in a cylinder and the cylinders, in turn, are secured to the frame and a conduit is arranged for fluidly connecting like ends of the cylinders whereby movement of a piston in one of the cylinders is possible only when the piston in the other cylinder moves in the opposite direction. In other words, it is a feature of the present invention that a pair of brake bands is mounted for arcuate movement on a frame with the brake bands connected to a fluid containing system whereby one of the brake bands can move through an arc only when the other brake band moves in the opposite direction and through the same arc. Means are arranged for contracting the brake bands in turn about the hoisting drum whereby a first brake band is locked to the hoisting drum and moves through its predetermined arc while a second brake band is released from the hoisting drum and moves in the opposite direction; when the first brake band has moved through its predetermined arc, the second brake band is contracted to lock it to the hoisting drum and the first brake band is released, the second brake band is then moved in the same direction of rotation as did the first brake band when it was locked to the hoisting drum and simultaneously, the first brake band returns to its original position. When the second brake band has moved through its arc with the hoisting drum, the first brake band is locked to the hoisting drum, the second brake band is released from the hoisting drum and the cycle is repeated.

It is a further feature of the present invention that any time at the option of the operator both brake bands maybe contracted thereby completely stopping the rotation of the hoisting drum. When it is desired to stop the rotation of the hoisting drum completely, both brakes may be contracted without altering the hydraulic system previously referred to and if subsequently the hoisting drum is to be released, the apparatus may be placed in operation for rotation of the hoisting drum at the same speed used prior to the complete stopping of the drum.

Turning now specifically to the drawing, the apparatus will first be described generally. A frame A" has a drum assembly B mounted thereon for rotation about a fixed axis. The frame and drum assembly may be a conventional hoisting apparatus or draw works, commercially available. Mounted on drum assembly B are brake band assemblies C and C'. Corresponding portions of brake band assemblies C and C are connected hydraulically with assembly D. Corresponding portions of brake band assemblies C and C' are also connected with system E; system E including partsshown within the dashed rectangle identified by numeral ii! on Figs. 1 and 7 and parts shown as the control panel designated by the numeral 8 in Fig. '7. The system E may be described as one adapted to operate through the medium of a compressible fluid maintained at superatmospheric pressure; this compressible fluid may, for example, be air, nitrogen, or fiue gas, but for convenience hereafter the material will be referred to as compressed air.

A handbrake assembly F is mounted on frame A and is arranged for applying a braking force to the brake drum assembly B for emergency operation. It is to be noted that, in order to illustrate the invention more adequately, the Fig. 2 is shown with a rope or line i I carried by drum assembly B whereas, in order to prevent confusion of such a showing with the various conduits on Fig. 1, the line Ii has been omitted from Fig. 1.

Drum assembly B is mounted on frame A for rotation about a fixed axis indicated by numeral i2 in Fig. 2. Drum assembly B defines cylindrical surfaces I3 and 13' adapted to cooperate with brake band assemblies C and C, respectively. Drum assembly B comprises a cylindrical surface I4 between the brake band assemblies arranged for receiving line il in the usual manner.

Brake band assemblies C and C' are exactly alike with the parts of assembly C identified by numerals, and corresponding parts of assembly C identified with corresponding primed numerals.

By reference to Fig. 2, brake band assembly C will be seen to include arcuate band i5 and arcuate band IS with ends of the hand held together with adjustable clamp II. A power unit comprising cylinder piston I9 arranged to reciprocate therein, and piston rod 20 with one end attached to piston i9 and projecting through the piston rod end of cylinder I3, is mounted by trunnions 2i to plates 22 carried by arcuate member l5. The free end of piston rod 20 is fastened through pin 23 to link 24 which has its other end secured to arcuate member l5 by pin 25. Lever 24 is pierced to receive a pin 26 which serves to attach an end of link 21 to link 24. Link 21 is also attached through pin 23 to clevis 23 which, in turn, is secured to the end of arcuate member i6 through pin 30. Pin 28 also serves to attach clevis 29 and link 21 to link 31 which, in tuin, is secured to arcuate member i5 through pin 3 A cylinder 33, with its lower end secured to frame A, has a piston 34 slidably mounted therein. Piston rod 35 is attached to the piston 34 and projects through the piston rod end of the cylinder. Piston rod 35 is secured to a projection 36 of arcuate member i5 by a pin 31. It may be noted that the arrangement of cylinder 33 with piston 34 mechanically connected to arcuate member l5 serves as a hold-down for the brake band when force is applied by means of piston l9 and cylinder i8. If desired, instead of relying upon the piston 33 and piston rod 35 as a hold-down means, a transverse opening 38 is provided in projection 36 which serves to receive a suitable means, not shown, such as a link and pin, securing projection 36 to frame A.

A valve member 39 is mounted on the piston rod end of cylinder 33 and a means 40 for operaging valve member 39 is mounted on piston rod 3 The parts making up auxiliary hand brake assembly F are shown in Figs. 1, 2, and 3. This assembly includes parallel shafts 4| and 42; shaft 4i is journaled to frame A through journals 43 and 44 and shaft 42 is journaled to the frame by journals 45 and 48. A hand lever 3 is mounted on the outboard end of shaft 4|. A pair of crank arms 41 is mounted on shaft 4| for rotation therewith and a pair of crank arms 48 is mounted on shaft 42 for rotation therewith; the ends of these pairs of crank arms are connected together through link 8. A second pair of crank arms 49 is also mounted on shaft 42 for rotation therewith with the aforesaid crank arms linked through members 50 and 5| and bolt 52 to equal izer 53. It will be seen that the lower surface of the equalizer 53 is slidably arranged on frame A.

One end of the equalizer 53 is connected through chain 55 to arcuate member 16 of brake band assembly C, while the other end of the equalizer member is connected through chain 55' to arcuate member iii of brake band assembly C. It is to be noted that with the lever arm in the position shown in the drawings, the chains 55 and 55' are slack, thereby allowing the brake band assemblies C and C to be operated by compressed air without bringing the hand operated brake into play; it will be obvious that movement of the hand lever 9, to rotate shaft 4| in a clockwise direction, as viewed in Fig. 2, will first take up the slack in chains 55 and 55' and then tighten the brake band assemblies C and C against surfaces 13 and I3, respectively, of the hoisting drum.

The hydraulic system D fluidly connecting the cylinders 33 and 33 of assemblies C and C includes a conduit 60 connected to the piston rod end of cylinder 33 and a conduit 60 fluidly connected to the piston rod end of cylinder 33'. The conduits 60 and 60' are fluidly connected guano with a branch line 6| containing check valves 62 and 63 and a conduit 64 containing check valves 65 and 66. That portion of conduit 6| between check valves 62 and 63. and that portion of conduit 64 between check valves 65 and 66 are connected with three branch lines 61, each controlled with adjustable needle valve 68. The hydraulic system fluidly connecting brake band assemblies B and 3' also includes a conduit 89 fluidly connecting the head end of cylinder 33 with the head end of cylinder 33'.

The arrangement of the hydraulic system D with check valves 62, 63, 65, and 66 is for the purpose of insuring that the liquid passing from conduit 68 to 68. and from conduit 68 to 68 will always flow in the same direction through needle valves 68. Now, if it be assumed that the fluid is to pass from the piston rod end of cylinder 33 to cylinder 33', the fluid passes through conduit 68, check valve 62, upwardly through one or more of the branch line 61, in parallel through one or more of adjustable needle valves 68, into conduit 64, through valve 86, and into conduit 68' and into the piston rod end of cylinder 33". If it be assumed that fluid is to pass from the piston rod end of cylinder 33' to the piston rod end of cylinder 33, liquid passes through conduit 68', through valve 63 in conduit 6|, and then through one or more of the branch lines 61 controlled by needle valves line I6 to conduit I8. The valve member-"I2 is 68; the fluid then passes through conduit 64 and check valve 65 to conduit 68 and thence into the piston rod end of cylinder 33.

It is not necessary that the line 69 and the head ends of cylinders 33 and 33' contain a liquid, but in order to provide for smoothness of operation, liquid is also placed in these parts; it will be obvious that, as piston 34 in cylinder 33 moves upwardly, and the liquid from the piston rod end of cylinder 33 passes to the piston rod end of cylinder 33', an equal amount of fluid is displaced from the head end of cylinder 33' through conduit 69 into the head end of cylinder 33 and similarly, when the piston in cylinder 33' moves upwardly and displaces fluid from the piston rod end of cylinder 33, an equal amount of liquid is displaced from the head end of cylinder 33.

The assembly E for supplying and controlling the flow of compressed air into cylinders I8 and I8 of brake band assemblies C and C includes a control panel 6 which is fluidly connected to a source of compressed air through an inlet H hereinafter designated as the main air line. Mounted on the control panel 6 is member I2 which may be described as a double valve mechanism having a single control member 13. Control member 13 may be in a neutral position with both of the valve members inoperative, or may be moved to a first position, for example upward, to operate a first valve member indicated in the drawing as I4, or it may be moved from the neutral position to a second position, for example downward, to operate the second valve element indicated in the drawing as 15. Branch line 16 connects the inlets of valve elements I4 and 15 to main air line II; the outlet of valve element 14 is connected to conduit 11, while the outlet of valve element I5 is connected to conduit 18.

It will be understood that movement of control member 13 from neutral to the first position allows fluid communication between main air line H through conduit I6 to conduit I1, while movement of control member I3 from the neuof the conventional type, having exhaust ports, not shown, which allow air to be bled from conduits TI and I8 when the control member 13 is returned to neutral position.

A conduit 88 connects to the main air line H and the flow of air through this conduit is controlled by valve 18 mounted on control panel 6. It may be mentioned that valve. 19 is preferably of the type adjusted with a hand wheel so that the constriction of flow through the valve may be adjusted by the operator and the valve left at this setting over substantial intervals of time.

A unit designated as double check valve 8| consists of a casing 82 having a member 83 slidably arranged therein with inlet ports 84 and 85 at the ends thereof and outlet port 86 at its center. The double check valve M is arranged so that fluid may pass from inlet port 84 to outlet port 86 when member 83 is adjacent inlet port 85 and so that fluid may pass from inlet port 85 to outlet port 86 when the movable member is adjacentinlet port 84. Inlet port 84 is fluidly connected to conduit 18 and inlet port 85 is fluidly connected to conduit 88. Outlet port 86 is connected to conduit 81.

Arranged in main air line II is a diaphragm valve 88 which is arranged to control the flow of air through main air line II. The operation of the diaphragm valve controlled by the pressure of fluid in diaphragm member 98 which is connected by conduit 89 to branch line 18. The outlet of valve 88 is connected to conduit 9|.

Also mounted on the control panel 6 is valve 82 having its inlet connected to the main air line through conduit 83 and-its outlet connected to conduit 94. The valve 82 may be of a commercially available type arranged normally to be maintained in a closed position and to be opened in detail in Figs. 4 and 5. Member I88 will not be described in detail. It will be understood that although the several parts of valve member I88 are not shown in detail, this member has exactly the same construction as valve member I88 with the like parts identified with corresponding primed numerals. Housing I8I has a member I82 slidably arranged therein. Slidable member I82 defines a passage I83 which may be described as being generally in the shape of a capital U. The base of the U-shaped fluid passage I83 is in fluid communication with an inlet I84 in housing I8I, while the upper portions of the U-shaped passage are fluidly connected either to outlet I85 or I86 in the housing I8I, depending upon the position of member I82. 1 If slidable member I82 is in the position, shown in the drawing hereinafter referred to as the first position, air passes from inlet port I84 through passage I83 to outlet port I 86; if the slidable member is at the other end of housing I82, hereinafter referred to as the second position, air passes from inlet port I 84 through passage I83 to outlet port I85. Slidable member I82 is also provided with a passage I81 at one end thereof and a second passage I88 at the other endthereof; these passages will hereinalter be referred to as exhaust passages. .When member I02 is in its first position, exhaust passage I01 allows communication between outletport I05 and outlet port I09 of the housing and, similarly, when member I02 is in the second position, exhaust passage I08 allows fluid communication between outlet ports I06 and outlet port I.

The slidable member I02 is connected to rod III passing through a suitable fluid-tight gland, not shown, of housing I02, and member I02 is connected to rod III similarly passing through a fluid-tight gland, not shown, in housing IN.

The adjacent ends of rods III and III are eon-- nected to opposite sides of diaphragm member H2. The end surfaces of member I02 cooperate with housing IM to form a substantially fluidtight seal and access to the space at the headhand end of housing IN is provided by inlet port IIO. Similarly, access to the head-hand of housing IOI' is provided by inlet port H.

The entire flow circuit of the compressed air system will now be described. The circuit is shown in Fig. '7. A relay valve I20 has its inlet connected to main air line I2I and its outlets connected by branch lines I22 and I22 to inlets I04 and I04 of valve members I00 and I00. Relay valve I20 is of a conventional type, with the operation of the relay controlled by the pressure in conduit 81 which fluidly connects the relay valve with the double check valve 8I. An exhaust port I23 is provided in the relay valve for exhausting air from lines I22 and I22 to the atmosphere when the relay is closed.

A second relay valve I24 has its inlet fluidly connected to main air line I25 and has its outlet lines connected through conduits I26 and I26, respectively. the ports I09 and I09 of valve members I00 and I00, respectively, to allow the brakes to be released under power; at all other times the relay valve functions as a quick release valve in emitting air from the head ends of cylinders I00 and I00. The operation of relay valve I24 is controlled by the air pressure in conduit 11, which is connected to valve assembly I2. Relay valve I24 is provided with an outlet I21 for exhausting lines I26 and I25 to the atmosphere when the relay valve is closed. I

It will be understood that the construction and use of relay valves are well known to the art.

The purpose of a relay valve is to relay or repeat the operation of a controlling valve or device. An inc ease of the control pressure actuates the relay valve to produce the same or a proportional pressure in an air cylinder; likewise, a reduction of the control pressure results in a similar or proportional reduction of cylinder pressure. With a relay valve in the pipe between the controlling valve and an air cylinder and connected to a large source of air supply, the controlling valve serves to pilot the large capacity flow to and from the air cylinder. The use of a relay valve thus provides that a small capacity controlling valve may be used to control the operation of a large capacity air cylinder.

In valve housing I08 outlet port I is fluidly connected to the head end of cylinder I8 in brake band assembly C through conduit I28, and outlet p'ort I06 is fluidly connected to the rod end of cylinder I8 through conduit I29. Similarly, the head end of cylinder I8 in brake band assembly C is connected to outlet I05 of assembly I00 through conduit I28 and the rod end of cylinder I8 is connected to outlet I06 through conduit I29.

In assembly I00 the inlet H0 is connected through conduit I30 to double check valve I3I. The double check valve I3I is similar in construction to double checkvalve 8|, previously described, and, accordingly, will not be described in detail, since this would be merely a repetition of the description of double check valve 8|. One of the inlet ports of double check valve I3I is connected through conduit I32 to cam-operated valve 39, which is connected to main air line I34. The other inlet of double check valve I3I is connected through line 94 to valve 92, heretofore described.

In assembly I00, inlet I I0 is connected through conduit I30 to cam-operated valve 39. which is connected to main air line I34.

In order for the brake assemblies C and C to maintain control of hoisting drum assembly B at all times, it is desirable when one brake band assembly is being released and the other bein engaged for that assembly being engaged to act more quickly than the assembly being released. To insure such an operation a check valve I35 is arranged in each of lines I28, I29 and I28 and I29. An enlarged view of one of the check valves I35 is shown in Fig. 6. It will be seen that the check valve consists of a valve body I36 definin an air passage I31 and arranged in the air passage is a member I38 attached with a hinge I39 to the valve body. Member I38 is pierced by a plurality of openings I40. For convenience, an arrow is placed adjacent each of check valves I35 in Fig. 6 to indicate the direction in which the flow of fiuid causes member I38 to be raised to clear the passage to allow free flow of air through the valve. When the air flows through valve I35 in the direction opposite from that in which the arrow is pointing, the air is forced to pass through the relatively small openings I40.

The arrangement of valves I35 in each of lines I28, I29, and I28 and I29 insures that the brake band assembly being tightened on the hoisting assembly operates more quickly than that which is being released. If it be assumed, for example, that brake band assembly C is bein tightened while assembly C is being released, the air flows freely through valve I35 in line I29 to the piston rod end of cylinder I8 and flows freely through line I28 and valve I35 from the head end of cylinder I8; in other words, the air flows freely into the inlet and from exhaust of the cylinder which is to apply the brake band. At the same time the flow of air into the head end of cylinder I8 is restricted by the necessity of the air passing through the ports I40 of valve I35 in line I28 and similarly the exhaust of air fro-m the piston rod'end of cylinder I8 is restricted by being forced to flow through the openings I40 of the valve I35 in line I29. When assembly C is being engaged to the brake drum and assembly C disengaged, the same conditions are established, that is to say, the flow of fluid into and from cylinder I8 to engage brake assembly C is rapid while the flow of fluid into and from cylinder I8 to release the brake assembly C is restricted.

It will be evident that the mechanism for engaging and disengaging brake band assemblies C and C to drum asscmbiy B may be motivated by arrangements other than the use of air pressure as shown in Figs. 1 to 7, inclusive. A mechanism for operating the valve assemblies I00 and I00 employing electricity as the means of controlling these valves is shown in Fig. 8.

In Fig. 8 the line: I22, I26, I28, I29, and I22, I26, I26, and I29 are connected in exactly the same manner as in the circuit diagram of Figs. 1 and 7. The brake band assemblies C and C (not shown in Fig. 8 but identical with the showing in the embodiment illustrated in Figs. 1 to 7) also have mounted thereon the switch activating mechanisms 40 and 40' corresponding exactly to that shown in Figs. 1, 2, and 7. Similarly, line II represents a main air line in the same way as in preceding Figs. 1 and 7. The means for operating valves I and I00, however, differs from that of the previously described embodiment employing an electrical circuit rather than a fluid means.

In Fig. 8 main air line II is connected to inlet port IIO of valve mechanism I00 by means of a branch line I50 controlled by valve I4I. Similarly, main air line II is connected to inlet port I I0 of valve I00 by branch line I50 controlled by valve I4I. Valves I and HI are operated by electricity and may be any of the conventional types known to the art. Inasmuch as such valves are known, the details of the construction of valves HI and MI will not be described. An electrical conductor I42 is shown attached to valve I through branch line I43 and to valve I4I through branch line I44; a plus sign indicates that conductor I42 is connected to a positive source of electricity. A conductor I45 having a switch I46 arranged therein is connected to valve I; a minus sign indicates that conductor I45 is connected to a negative source of electricity. Conductor I45 containing a switch I46 is similarly indicated as connecting valve I4 I to a negative source of electricity.

Switch I46 cooperates with element 40 in a manner analogous to'that which valve 39 cooperates with element 40 in the embodiment of Figs. 1 to 7. Similarly, switch I46 cooperates with element 40 in a manner analogous to that of valve 39 and element 40 of the embodiment of Figs. 1 to 7. While switches I46 and I46 are shown diagrammatically only, it will be'understood that it is usually desirable to employ the switches known as limit switches for this purpose; such a switch is positively acting in that once it is closed a substantial movement of element 40 is necessaryibefore the switch will open and mere vibration of the assembly will not open the switch. When element 40 contacts switch I46 and closes it, current is allowed to pass to valve MI and opens the valve whereby air from the main air line flows through branch line I50 to inlet port IIO of valve I00 and operates the valve in the same manner as air passing through line I30 to inlet port IIO of the embodiment of Figs. 1 to 7, and when element 40 moves out of contact with switch I46 valve I4I' closes as does valve 39 when element 40 moves out of contact with it. Similarly, when element 40 closes switch I46 the current passes to valve MI and opens it to allow air to flow from main air line H through branch line I50 to inlet port 0' of valve I00 and activates it in the same way. When element 40 moves out of contact with switch I46, valve MI is closed and prevents communication between main air line H and branch line I50. It will be understood that in the embodiment illustrated generally any suitable type of electrically operated valves, with a suitable type of electricity, either alternating or direct current, may be employed as desired. I

The operation of the assembly of the present invention in what may be termed the normal operation of the device, that is, when paying out line under load will now be described. When the 4 assembly C is reversed so that it moves in a clockwise direction, the assembly C then moves in a counterclockwise direction. This motion of the brake band assemblies may be described as a walking motion.

The relationship of the various parts with the normal operation described in the preceding paragraph will now be examined in detail. With the parts in the relative positions indicated in Fig. 1, drum assembly B is moving in the counterclockwise direction, as viewed in Fig. 2, under the load supported by cable II, and brake band assembly C is engaged with the brake drum I3 and moving with it, while assembly C is loose on brake drum I3 and moving in the opposite direction from brake band assembly C. Control member 73 is in its neutral position and valve 19, which may be of the pressure regulating type, is in the open position, these control valves having been given these settings by the operator for initiating normal operation. Pressure regulating valve 19 is so set that the pressure in line is lower than the pressure in line I8 when line 18 is fluidly connected with main air line II through valve I2 and line I6. With control member I3 and valve 19 in the aforementioned positions, air flows from main line H through branch line 80, valve I9, double check valve 8I and line 81 to relay valve I20. Air also flows through double check valve 8| into line 61 because slidable element 83 is forced to the left extremity of double check valve 6| by reason of the pressure in line 80 being greater than the air pressure in line I8, line 18 having previously been bled by valve I2, which is of the bleeder type, when control member I3 was placed in the neutral position. Relay valve I20 is held open by means of the pressure exerted by air flowing in line 81. With relay valve I 20 open air flows from main air line I2I to branch lines I22 and I22, thence to valve assembly I00 and I00, respectively. Slidable element I02 is located in valve assembly I00 adjacent the end defining port II 0 and consequently the air in line I22 enters valve assemly I00 through port I04, fluid passage- I03, port I06, and through line I29 into the piston rod end of cylinder I8; this causes air pressure to be exerted against the piston rod end of piston I9 and thus maintaining brake band assembly C' tight on drum I3. While air is flowing through line I22, it is also flowing through line I22, entering valve assembly I00 through port I04. Slidable element I02 is located in valve assembly I00 opposite the end which defines port IIO', inasmuch as slidable elements I 02 and I02 are connected together by means of rods III and I I I and diaphragm member II2. With member I02 in the aforementioned position, air entering valve assembly I00 through lines I22 and port I04 flows through passage I03 and port I06 into line I28 and into the head end of cylinder I 8. This causes air pressure to be exerted against the head end of piston I9 thus maintaining brake band assembly C loose on brake drum I3. While brake band assembly C is thus engaged and brake band assembly C is disengaged, piston 34 mechanically connected to brake band assembly C is moving upwardly while piston 34 mechanically connected to brake band assembly C is movin downwardly. The upward motion of piston 34 is produced by the pull of cable II on brake drum assembly B causing rotation thereof. Inasmuch as brake band assembly C is engaged with brake drum assembly B at brake drum I3, brake band assembly C is also moving arcuately thus causing piston 34 to move upwardly in cylinder 33. As previously pointed out. cylinders 33 and 33 contain fluid and the portion of cylinder 33 above piston 34 is fluidly connected with the portion of cylinder 33 above piston 34' by means of lines 60, 64, 67, and 60'. The portion of cylinder 33 below piston 34 is fluidly connected with the portion of cylinder 33 below piston 34'. Line BI also fluidly connects lines 60 and 60'. Line 54 contains check valves 65 and 66, while line 6I contains check valves 62 and 83, the aforementioned check valves permitting unidirectional flow in the lines in which they are located. Lines GI and 64 are fluidly connected by means of one or more of branch lines 81 containing adjustable needle valve 68. As piston 34 moves upwardly, the fluid contained in the upper portion of cylinder 33 flows through line 60, check valve 65, line 64, line 61, controlled by needle valve 08, line 8I, check valve 63, and line 80 into the upper portion of cylinder 33 forcing piston 34 downwardly therein. Since brake assembly C is mechanically connected to piston 34', brake assembly C is also caused to move arcuately to follow piston 34. As brake band assembly C reaches the end of its downward stroke, member 40 contacts valve 39, thereby opening valve 39' momentarily which, in turn, allows compressed air to flow from main line I34, through valve 39' and line I30 and to enter the end of assembly I which pushes movable element I02 away from inlet IIO; simultaneously element I02 moves toward inlet I I0 in assembly I00. Upon this movement of element I02 compressed air in line I22 flows into valve element I00 through'port I04, through passage I03, port I05, and line I28 into the head end of cylinder I8 thereby driving piston I9 toward the rod end of cylinder I8 and releasing brake band assembly C from brake drum I3. Conversely, on movement of element I02 toward inlet H0 in valve element I00, the air in line I22 flows into valve element I00 through port I04 into passage I03 through port I05 and line I29 into the piston rod end of cylinder I8 thereby driving piston I9 toward the head end of cylinder I8 and tightening brake band assembly C on brake drum I3. Tightened brake band assembly C rotates with brake drum assembly B thereby causing piston 34 to move upwardly and simultaneously piston 34 is moving downwardly while brake band assembly C, mechanically connected to piston 34, is moving arouately in the opposite direction lrom assembly C. As brake band assembly C rotates with drum assembly B. the rotation of drum assembly B being produced by the pull of cable II, piston 34, being mechanically connected to brake band assembly C, moves upwardly toward the piston rod end of cylinder 33'. While piston 34' is moving upwardly toward the piston rod end of cylinder 33, piston 34 is moving downwardly toward the head end of cylinder 33, the downward movement of piston 34 being caused by the flow of fluid from cylinder 33 through fiuidly connecting conduits 50, 84, 61. BI, and 60-into piston 33. Inasmuch as brake band assembly C is mechanically connected to piston 34, it is caused to move arcuately in cooperation with piston 34. The

Ill)

movement of brake band assembly C in due course brings member 40 into contact with valve 39 and opens this valve momentarily. The opening of valve 39 causes air to flow in line I30 which in turn causes movable element I02 in assembly I00 to move away from inlet end I I0 and simultaneously causesmovable element I02 in assembly I00 to move toward inlet end IIO; this change in the valve setting admits air to the piston rod end of cylinder I8 and to the head end of cylinder I8, as hereinbefore described, thereby tightening brake band assembly C and releasing brake band assembly C, thus allowing the cycle heretofore described to be repeated.

The manipulation of valve members by an operator in order to control the movement of the hoisting drum will now be described. If it is desired to hold the drum stationary, this may be done by moving control member I3 to operate valve mechanism I5 which allows air to flow from main air line II and line I6 into lines I8 and 89, the pressure in lines I8 and 89 being equal to the pressure in main air line II. The admission of main line air pressure to lines 89 and I8 simultaneously actuates diaphragm 90 to open valve 88 and forces slidable element 83 to the right extremity of double check valve assembly 8| to permit air to flow from line I8 through valve assembly 8| into line 81. The opening of valve 88 permits main line air pressure to enter line 92 and to spread diaphragm member II2 which, in turn, moves element I02 in assembly I00 toward the inlet end H0 and element I02 in assembly I00 toward inlet end H0. The air admitted to line 87 through double check valve assembly 8I actuates relay I20, thereby permitting air from main air line I2I access through lines I22 and I22 to inlets I04 and I04 of assemblies I00 and I00, respectively. The expansion of diaphragm element II2 together with the admission of air to assemblies I00 and I00 allows air to pass through branch line I22, passage I03, and line I29 to the piston rod end of cylinder I8, and simultaneously allows air to pass through conduit I22, passage I03, and conduit I29 to the piston rod end of cylinder I8; this tightens brake band assemblies C and C simultaneously and prevents any rota-- tion of drum B. The manipulative steps for bringing the assembly from rest to normal rotation under load are as follows. Valve I9 is opened and valve mechanism I5 may then be closed by the movement of control member 13 to neutral position. These steps allow air to bleed from lines I8 through valve I2 and the double check valve 8I to respond to pressure in line 80, with air passing from main air line II through line and valve 19, double check valve 8| and conduit 81 to relay I20. The movement of controlmember I3 to neutral position allows diaphragm valve 88 to close with the pressure in line 9I bleeding off through outlet 08'. To assure that the valve elements I02 and I02 are in proper position, it is desirable then to move these elements into a known position; this could be done by the operator going from his control board and operating manually either valve 39 or valve 39, but for convenience valve 92, connected in parallel with valve 39, is arranged at the control panel and operation of this valve allows air to pass from main air line II to double check valve I3I. The air pressure in line 94 controls the position of the double check valve I3I and allows air to flow through conduit I30 and to inlet I I0, moving element I02 away from inlet IIO which, in turn, causes movement of element I02 toward inlet IIO.

In other words, operation of valve 92 positions the movable parts of elements I III! and I so that air flows into the rod end of cylinder I8 and tightens brake band assembly C, while air is exhausted from the rod end of cylinder I8 of brake band assembly C, thereby releasing this assembly. The manipulation of valve 92 is the last manipulative step in the starting operation and the assembl then continually pays out line, or walks at a speed which is controlled by the rate liquid flows through one or more valves 68.

If it is desired to release both brake bands simultaneously, as when running a drill stem into the borehole, this may be done by moving control member 13 to operate valve mechanism 12. It is desirable to release both brakes only after both of the brakes have been applied, that is to say, after diaphragm member H2 has been expanded to position member I02 with its end adjacent inlet III) and member I02 with its end adjacent inlet 0'; the elements I02 and I02 being in this position, the opening of valve 12 allows air from the main air line H to fiow through conduits 16 and 11 to operate relay I24 which, in turn. allows air to pass from main air line I25 through relay I24 and to branch lines I26 and I26 which are connected to housings IOI and NH at ports I09 and I09, respectively, and the air then passes through exhaust passages III! and I01, respectively, conduits I28 and I28, respectively, and to the head ends of cylinders I8 and I8, respectively.

From the above description it will be seen that the device of the present invention allows the rotation of a hoisting drum, when paying out line under load, to be accurately and easily controlled. It will also be seen that the assembly allows the rotation of the drum to be stopped completely at any time at the option of the operator and also allows the brake band assembly to be completely disengaged from the hoisting drum at any time at the option of the operator. It will also be seen that in the event of an emergency when the power supply fails, the brake assembly may be operated manually to engage the brake bands frictionally with the brake bands in the conventional manner.

While I have disclosed specific embodiments illustrating the device of the present invention, it will be obvious to the workman skilled in the art that various changes in the shape, size and proportions of the several parts of the apparatus may be made without departing from the scope of the invention and itis my intention to embrace such changes by the hereto appended claims.

I claim:

-1. Apparatus adapted to apply a restraining force to a hoisting drum mounted on a frame for rotation about a fixed axis comprising, in combination, a first brake band adapted to cooperate with the hoisting drum to apply braking force thereto, a first power meansmounted on a first brake band and adapted to engage releasably the first brake band with the drum, a, second brake band mounted for engagement with a surface of the hoisting drum, 9. second power means car- 14 3. An apparatus adapted to apply a restraining force to a hoisting drum mounted on a frame for rotation about a fixed axis comprising, in combination, a first brake band mounted on the frame ried by the second brake band and adapted to engage releasably the second brake band with the surface of the drum and control means arranged for limited arcuate movement about an axis coinciding with the axis of the hoisting drum, a second brake band mounted on the frame for limited arcuate movement about an axis coinciding with the hoisting drum, 9. first power means carried by the first brake band arranged to engage releasably the first brake band with the hoisting drum, a second power means carried by the second brake band adapted to engage releasably the second brake band with the hoisting drum and control means arranged selectively to operate the first and second power means in sequence and simultaneously;

4. An assembly including a frame, a hoisting drum mounted on the frame for rotation about a fixed axis and defining at least two cylindrical surfaces having an axis coinciding with the axis of rotation and adapted for cooperation with brake bands, a first brake band mounted on the frame for limited angular movement about the axis of rotation of said drum with respect to the frame and adapted to cooperate with one Of said cylindrical surfaces, a second brake band mounted on the frame for limited angular movement about the axis of rotation of said drum and adapted to cooperate with the second cylindrical surface, means mounted on the first band arranged to tighten the band to prevent relative movement between the band and the drum, means mounted on the second band adapted to tighten the second band and prevent relative movement between the second hand and the drum, a first cylinder mounted on the frame adjacent the first band, a first piston slidably mounted in 'said cylinder, means mechanically linking said first piston with the brake band including a first piston rod mechanically connected to said piston and extending through an end of the cylinder, a second piston mounted on the frame adjacent the second band, a second piston arranged for reciprocation in said second cylinder, means including a second piston rod connected to the second piston and extending through an end of the second cylinder mechanically connecting the second piston with the second hand, a conduit including an adjustable orifice fluidly connecting the piston rod end of the first cylinder with the piston rod end of the second cylinder, means arranged to contract the first band to prevent relative movement between said band and the drum and to release the second band to allow relative movement between the band and the.

rotation about a fixed axis comprising, in combination, a first brake band mounted on the frame and arcuate movement thereof a predetermined distance about the axis of rotation of the body and adapted to engage with a cylindrical surface defined by the body, a second brake band mounted on the frame and arranged for a limited arcuate movement about the axis of rotation of said body, a first cylinder mounted on the frame adjacent the first brake band, a first piston mounted for reciprocation in the cylinder, means including a first piston rod connected to the piston and extending through one end of the cylinder mechanically connecting the piston with the first brake band, a second cylinder mounted on the frame adjacent the second brake band, a second piston arranged for reciprocating in the'second cylinder, means including a second piston rod connected to the second piston and extending through one end of the second cylinder mechanically connecting the second piston with the second band, a conduit including an adjustable valve fluidly connecting the piston rod end of the first cylinder with the piston rod end of the second cylinder, a first releasable means mounted on the first brake band arranged for tightening the first brake band to prevent relative movement between the band and the drum, a second releasable means mounted on the second band arranged to tighten the second band to prevent relative movement between the second band and the drum, means including a valve mechanism mounted on the first band and arranged to be activated when the first'band reaches a predetermined position with respect to the frame for activating the band tightening mechanism'mounted on the first band, and for releasing the band tightening mechanism mounted on the second band and means including a valve mounted on a, second band for activation when the second band reaches a predetermined position with respect to the frame for activating the second band tightening mechanism and releasing the first band tightening mechanism.

6. A device adapted to control the operation of brake bands for controlling the rate of rotation of a hoisting drum comprising, in combination, a first cylinder, a first piston arranged for reciprocating in the first cylinder, a first piston rod secured to said first piston and extending through one end of the cylinder, said piston rod being adapted for connecting with a brake band for contracting said band, a second cylinder, a second piston arranged for reciprocation in the second cylinder, a second piston rod connected to the second piston and extending through an end of the second cylinder and adapted to be attached to a second brake band for contracting the band, a first and second master valve, said master valves each being provided with a slidable piston and the pistons of the two master valves mechanically connected, an inlet line adapted to be connected to a supply of compressible fluid at superatmospheric pressure connected to each of the master valves, a conduit fluidly connecting the first master valve with the piston rod end of the first cylinder for supplying compressible fluid to the piston rod end of the cylinder when the piston of the firstmachine valve is in its first position,

and for exhausting air when said piston of the first master valve is in its second position and a second conduit connecting the head end of the first cylinder with the first master valve for connecting said head end with the compressible fluid at superatmospheric pressure when the piston in the first master valve is in its second position and exhausting fluid from the head end of the first cylinder when the piston of the master valve is in its first position, a third conduit fluidly connectin the second master valve with the piston rod end of the second cylinder for supplying compressible fluid at superatmospheric pressure to said piston rod end when the piston of the second master valve is in its first position and for exhaustin compressible fluid when the piston of the second master valve is in a second position.

a fourth conduit fluidly connecting the second master valve with the head end of the second cylinder for supplying compressible fluid thereto when the piston of the second master valve is in its second position and for exhausting fluid therefrom when said piston of the master valve is in its first position, and means activated by movement of one brake band for moving the piston of the first and second master valves from their second to their first and their first to their second positions, respectively, and means arranged to be activated by the other brake band for moving the pistons of the first and second master valves from their first to second and second to first positions, respectively.

7. A device in accordance with claim 6 in which the means mechanically linking the piston of the first and second master valves is arranged for forcing both pistons to their first position.

8. A hoisting drum assembly comprising, in combination, a frame, a hoisting drum mounted on the frame for rotation about a fixed axis and defining a first surface and a second surface symmetrical with said axis, a first brake assembly mounted on the frame for movement through a predetermined are having an axis coinciding with the axis of the drum and mechanically linked to a first element and adapted to assume a first and a second position, a second brake assembly mounted on the frame for movement through a predetermined arc having an axis and magnitude corresponding to the arc of movement of the first brake assembly and mechanically linked to a second element and adapted to assume a first and a second position, a first element carried by the first brake assembly and defining a surface adapted to engage frictionally with the first surface of the drum, a second element carried by the second brake assembly and defining a surface adapted to engage frictionally with the second surface of the drum, means fluidly connecting the first and second brake assemblies and arranged to cause movement of the brake assemblies in opposite directions, a means mounted on the first brake assembly arranged to engage the first element with the first surface of the brake drum and to disengage the second element frm the second surface of the brake drum when the first brake assembly is in its first position and means carried by the second brake assembly adapted to engage the second element with the second surface of the brake drum and disengage the first element from the first surface of the brake drum when the second brake assembly is in its first position.

9. An apparatus adapted to apply a restraining force to a hoisting drum mounted on a frame for rotation about a fixed axis comprising, in combination, a first brake band mounted on the frame for limited arcuate movement about an axis coinciding with that of the drum, a second brake band mounted on the frame for limited arcuate movement about an axis coinciding with that of the drum and control means arranged selectively to engage and disengage said brake bands in sequence and to engage and disengage said brake bands simultaneously.

10. A feed-off means for a hoisting drum mounted on a frame for rotation about a fixed axis comprising, in combination, a first braking means mounted for arcuate movement about an axis coinciding with that of the drum, a first piston and cylinder assembly secured to said first braking means and to the frame arranged for relative longitudinal movement between the piston and cylinder upon arcuate movement 01' said first braking means, a second braking means REFERENCES CITED mounted for arcuate movement about an axis The following references are of record in the coinciding with that of the drum, a second pisfile of this patent: ton and cylinder assembly secured to said second 5 braking means and to the frame arranged for UNITED STATES PATENTS relative longitudinal movement between the pis- Number Name Date 7 ton and cylinder upon arcuate movement of said 1,711,886 Ginter May '7, 1929 second braking means and control means ar- 1,805,808 Crum May 19, 1931 ranged selectively to engage and disengage said 10 1,932,685 Black Oct. 31, 1933 first and second braking means mechanically with said hoisting drum.

ROBERT R. CROOKSTON. 

